ASP.NET health monitoring allows production and operations staff to manage deployed Web applications. The System.Web.Management namespace contains the health-event types responsible for packaging application health-status data and the provider types responsible for processing this data. It also contains supporting types that help during the management of health events.

Application lifetime events include events such as application startup and shutdown events. If an application is terminated, you can determine why by viewing the related event message field.

When a WebApplicationLifetimeEvent instance occurs, ASP.NET health monitoring updates the Application Lifetime Events performance counter. You can log these events by adding the WebApplicationLifetimeEvent object to the rules subsection of the healthMonitoring section of the configuration file, as shown in the following example.

The Application Lifetime Events performance counter contains the sum total of all ASP.NET lifetime events. To view this performance counter in System Monitor (PerfMon), in the Add Counters window select ASP.NET from the Performance object drop-down list. Select the Application Lifetime Events performance counter, and click the Add button. For more information, see "Using the System Monitor (PerfMon) with ASP.NET Applications" on MSDN. If you allow events to be logged by the standard EventLogWebEventProvider, you can view them in Event Viewer by selecting the Application log. For more information, see Event Viewer in the Windows Server 2003 documentation on TechNet.

Caution

Because the WebApplicationLifetimeEvent object is a high-volume event, logging it is resource-intensive and might slow down your system. It can also cause other events to be overwritten in the case of the EventLogWebEventProvider class due to the high volume of events and the way the event logging works.

Note

In most cases you will be able to use the ASP.NET health-monitoring types as implemented, and you will control the health-monitoring system by specifying values in the healthMonitoring configuration section. You can also derive from the health-monitoring types to create your own custom events and providers. For an example of deriving from the WebApplicationLifetimeEvent class, see the example provided in this topic.

Notes to Inheritors

When formatting your custom event information for display, override the FormatCustomEventDetails method rather than the ToString method. This will avoid overwriting or tampering with sensitive system information.

The following configuration-file excerpt shows how to configure the healthMonitoring section of a configuration file to add the SampleWebApplicationLifetimeEvent code defined above to the ASP.NET health-monitoring system. To add the event to the system, you must define the event by adding a new entry to the eventMappings section and map the event to a provider by adding a new entry to the rules section.